yes, I keep the same form factor. The size of the controller feels just right. An attempt to make it with 16 knobs resulted in bulky, ugly device.
What is on the drawing board, greatly inspired by input from @NewIgnis and by what I saw on @phonaak desk, is a docking station for Electra One, that would offer additional 24 pots, a set of extra buttons to switch pages, presets, modes. There would be also an extra narrow LCD and larger encoder. The docking station would also feature more USB ports and a power supply. I am about to make a few prototypes. I am not sure if and when it would be actually manufactured.
mk1 with firmware 3.0 and higher handles large SysEx messages. The difference between mk1 and mkII in this is that while mk1 stores larger SysEx messages in relatively slow external RAM (actually the unused part of the video RAM), mkII will do the work in SDRAM directly connected to the processor. It means much faster and without multiplexing data transfers with refreshing the graphics on the LCD.